<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .clearfix{
            overflow:hidden;
        }

        .box{
            overflow: auto;
            background-color:skyblue;
            width:60%;
            height: 300px;
        }
        .innerbox{
            background-color:pink;
            width:20%;
            height: 50px;
            margin: 1px;
            float:left;
        }
        .footer{
            background-color:pink;
            width:20%;
            height: 50px;
        }

    </style>
</head>
<body>
    <div class = "box">
        <div class = "clearfix">
            <div class = "innerbox"></div>
            <div class = "innerbox"></div>
        </div>
        <div class = "footer"></div>
    </div>
</body>
</html>